The mission of the Center for AIDS Prevention Studies (CAPS) is to conduct domestic and international research to prevent the acquisition of HIV and to optimize health outcomes among HIV-infected individuals. We propose a set of cores that will stimulate new research projects to keep pace with the ever-changing epidemic, provide necessary services to CAPS scientists and our extensive portfolio of research projects, and provide the platform for scientific interactions to advance and enhance multidisciplinary research in AIDS prevention and policy. We are requesting funding for the next five years to support six cores essential to our work: 1) The Administrative Core to provide leadership to CAPS scientists, stimulate innovation in research, provide organizational management, and perform monitoring and evaluation of the Center; 2) The Developmental Core to mentor investigators and help them flourish;provide pilot funds for innovative projects and ensure the scientific excellence and timeliness of CAPS science; 3) The Methods Core to provide support for training and consultations in research design and methods as well as state-of-the art data collection, management and analysis; 4) The Technology and Information Exchange Core to disseminate science to community, bringing community expertise to scientists, and support community collaborative research; 5) The Policy &Ethics Core to ensure that CAPS research meets the highest ethical standards, is communicated appropriately to policy makers and to support policy and ethics research; 6) The International Core to facilitate international collaborative research, support systematic scientific reviews, and inform the CAPS community about international research.